Technical Abstract:
Epidermal conductance (ge) is the loss of water vapor from leaves when stomata are closed. An experiment was conducted to compare epidermal conductance values of peanut genotypes with varied levels of field resistance to drought to assess ge as a potential drought response trait in peanut. Epidermal conductance was computed using the equation ge = ('FW/t)*(1/A)*1/(el-ea), where 'FW is change in fresh weight of a detached leaf over time t, A is the area of the leaf, and (el-ea) is the absolute humidity gradient between the leaf and the ambient air inside the measuring chamber. Water loss from leaves occurred linearly after 1 hr. No differences in ge were detected among genotypes or drought response groups. Based on these preliminary results, ge does not appear to vary much across peanut genotypes with different responses to drought.